r26868 seems to have some issues. It works well as long as all processes are started on the same node (aka. there is a single daemon), but it breaks with the error message attached below if there are more than two daemons.

$ mpirun -np 2 --bynode ./runme
[node01:07767] [[21341,0],1] ORTE_ERROR_LOG: A message is attempting to be sent to a process whose contact information is unknown in file ../../../../../ompi/orte/mca/rml/oob/rml_oob_send.c at line 362
[node01:07767] [[21341,0],1] attempted to send to [[21341,0],2]: tag 15
[node01:07767] [[21341,0],1] ORTE_ERROR_LOG: A message is attempting to be sent to a process whose contact information is unknown in file ../../../../ompi/orte/mca/grpcomm/base/grpcomm_base_xcast.c at line 157

I confirm that applying the reverted commit brings the trunk to a normal state.